log.c

关于tor匿名通信的源代码

/** Add a log handler named <b>name</b> to send all messages in <b>severity</b>
 * to <b>stream</b>. Copies <b>severity</b>. Helper: does no locking. */
static void
add_stream_log_impl(log_severity_list_t *severity,
                    const char *name, FILE *stream)
{
  logfile_t *lf;
  lf = tor_malloc_zero(sizeof(logfile_t));
  lf->filename = tor_strdup(name);
  lf->severities = tor_memdup(severity, sizeof(log_severity_list_t));
  lf->file = stream;
  lf->next = logfiles;

  logfiles = lf;
  _log_global_min_severity = get_min_log_level();
}

/** Add a log handler named <b>name</b> to send all messages in <b>severity</b>
 * to <b>stream</b>. Steals a reference to <b>severity</b>; the caller must
 * not use it after calling this function. */
void
add_stream_log(log_severity_list_t *severity,
               const char *name, FILE *stream)
{
  LOCK_LOGS();
  add_stream_log_impl(severity, name, stream);
  UNLOCK_LOGS();
}

/** Initialize the global logging facility */
void
init_logging(void)
{
  if (!log_mutex)
    log_mutex = tor_mutex_new();
}

/** Add a log handler to receive messages during startup (before the real
 * logs are initialized).
 */
void
add_temp_log(int min_severity)
{
  log_severity_list_t *s = tor_malloc_zero(sizeof(log_severity_list_t));
  set_log_severity_config(min_severity, LOG_ERR, s);
  LOCK_LOGS();
  add_stream_log_impl(s, "<temp>", stdout);
  tor_free(s);
  logfiles->is_temporary = 1;
  UNLOCK_LOGS();
}

/**
 * Add a log handler to send messages in <b>severity</b>
 * to the function <b>cb</b>.
 */
int
add_callback_log(log_severity_list_t *severity, log_callback cb)
{
  logfile_t *lf;
  lf = tor_malloc_zero(sizeof(logfile_t));
  lf->severities = tor_memdup(severity, sizeof(log_severity_list_t));
  lf->filename = tor_strdup("<callback>");
  lf->callback = cb;
  lf->next = logfiles;

  LOCK_LOGS();
  logfiles = lf;
  _log_global_min_severity = get_min_log_level();
  UNLOCK_LOGS();
  return 0;
}

/** Adjust the configured severity of any logs whose callback function is
 * <b>cb</b>. */
void
change_callback_log_severity(int loglevelMin, int loglevelMax,
                             log_callback cb)
{
  logfile_t *lf;
  log_severity_list_t severities;
  set_log_severity_config(loglevelMin, loglevelMax, &severities);
  LOCK_LOGS();
  for (lf = logfiles; lf; lf = lf->next) {
    if (lf->callback == cb) {
      memcpy(lf->severities, &severities, sizeof(severities));
    }
  }
  _log_global_min_severity = get_min_log_level();
  UNLOCK_LOGS();
}

/** Close any log handlers added by add_temp_log() or marked by
 * mark_logs_temp(). */
void
close_temp_logs(void)
{
  logfile_t *lf, **p;

  LOCK_LOGS();
  for (p = &logfiles; *p; ) {
    if ((*p)->is_temporary) {
      lf = *p;
      /* we use *p here to handle the edge case of the head of the list */
      *p = (*p)->next;
      close_log(lf);
      log_free(lf);
    } else {
      p = &((*p)->next);
    }
  }

  _log_global_min_severity = get_min_log_level();
  UNLOCK_LOGS();
}

/** Make all currently temporary logs (set to be closed by close_temp_logs)
 * live again, and close all non-temporary logs. */
void
rollback_log_changes(void)
{
  logfile_t *lf;
  LOCK_LOGS();
  for (lf = logfiles; lf; lf = lf->next)
    lf->is_temporary = ! lf->is_temporary;
  UNLOCK_LOGS();
  close_temp_logs();
}

/** Configure all log handles to be closed by close_temp_logs(). */
void
mark_logs_temp(void)
{
  logfile_t *lf;
  LOCK_LOGS();
  for (lf = logfiles; lf; lf = lf->next)
    lf->is_temporary = 1;
  UNLOCK_LOGS();
}

/**
 * Add a log handler to send messages to <b>filename</b>. If opening
 * the logfile fails, -1 is returned and errno is set appropriately
 * (by fopen).
 */
int
add_file_log(log_severity_list_t *severity, const char *filename)
{
  FILE *f;
  logfile_t *lf;
  f = fopen(filename, "a");
  if (!f) return -1;
  LOCK_LOGS();
  add_stream_log_impl(severity, filename, f);
  logfiles->needs_close = 1;
  lf = logfiles;
  _log_global_min_severity = get_min_log_level();
  UNLOCK_LOGS();

  if (log_tor_version(lf, 0) < 0) {
    LOCK_LOGS();
    delete_log(lf);
    UNLOCK_LOGS();
  }

  return 0;
}

#ifdef HAVE_SYSLOG_H
/**
 * Add a log handler to send messages to they system log facility.
 */
int
add_syslog_log(log_severity_list_t *severity)
{
  logfile_t *lf;
  if (syslog_count++ == 0)
    /* This is the first syslog. */
    openlog("Tor", LOG_PID | LOG_NDELAY, LOGFACILITY);

  lf = tor_malloc_zero(sizeof(logfile_t));
  lf->severities = tor_memdup(severity, sizeof(log_severity_list_t));
  lf->filename = tor_strdup("<syslog>");

  lf->is_syslog = 1;

  LOCK_LOGS();
  lf->next = logfiles;
  logfiles = lf;
  _log_global_min_severity = get_min_log_level();
  UNLOCK_LOGS();
  return 0;
}
#endif

/** If <b>level</b> is a valid log severity, return the corresponding
 * numeric value.  Otherwise, return -1. */
int
parse_log_level(const char *level)
{
  if (!strcasecmp(level, "err"))
    return LOG_ERR;
  if (!strcasecmp(level, "warn"))
    return LOG_WARN;
  if (!strcasecmp(level, "notice"))
    return LOG_NOTICE;
  if (!strcasecmp(level, "info"))
    return LOG_INFO;
  if (!strcasecmp(level, "debug"))
    return LOG_DEBUG;
  return -1;
}

/** Return the string equivalent of a given log level. */
const char *
log_level_to_string(int level)
{
  return sev_to_string(level);
}

/** DOCDOC */
static const char *domain_list[] = {
  "GENERAL", "CRYPTO", "NET", "CONFIG", "FS", "PROTOCOL", "MM",
  "HTTP", "APP", "CONTROL", "CIRC", "REND", "BUG", "DIR", "DIRSERV",
  "OR", "EDGE", "ACCT", NULL
};

/** DOCDOC */
static log_domain_mask_t
parse_log_domain(const char *domain)
{
  int i;
  for (i=0; domain_list[i]; ++i) {
    if (!strcasecmp(domain, domain_list[i]))
      return (1u<<i);
  }
  return 0;
}
#if 0
/** DOCDOC */
static const char *
domain_to_string(log_domain_mask_t domain)
{
  int bit = tor_log2(domain);
  if ((bit == 0 && domain == 0) || bit >= N_LOGGING_DOMAINS)
    return NULL;
  return domain_list[bit];
}
#endif

/** Parse a log severity pattern in *<b>cfg_ptr</b>.  Advance cfg_ptr after
 * the end of the severityPattern.  Set the value of <b>severity_out</b> to
 * the parsed pattern.  Return 0 on success, -1 on failure.
 *
 * The syntax for a SeverityPattern is:
 * <pre>
 *   SeverityPattern = *(DomainSeverity SP)* DomainSeverity
 *   DomainSeverity = (DomainList SP)? SeverityRange
 *   SeverityRange = MinSeverity ("-" MaxSeverity )?
 *   DomainList = "[" (SP? DomainSpec SP? ",") SP? DomainSpec "]"
 *   DomainSpec = "*" | Domain | "~" Domain
 * </pre>
 * A missing MaxSeverity defaults to ERR.  Severities and domains are
 * case-insensitive.  "~" indicates negation for a domain; negation happens
 * last inside a DomainList.  Only one SeverityRange without a DomainList is
 * allowed per line.
 */
int
parse_log_severity_config(const char **cfg_ptr,
                          log_severity_list_t *severity_out)
{
  const char *cfg = *cfg_ptr;
  int got_anything = 0;
  int got_an_unqualified_range = 0;
  memset(severity_out, 0, sizeof(*severity_out));

  cfg = eat_whitespace(cfg);
  while (*cfg) {
    const char *dash, *space;
    char *sev_lo, *sev_hi;
    int low, high, i;
    log_domain_mask_t domains = ~0u;

    if (*cfg == '[') {
      int err = 0;
      char *domains_str;
      smartlist_t *domains_list;
      log_domain_mask_t neg_domains = 0;
      const char *closebracket = strchr(cfg, ']');
      if (!closebracket)
        return -1;
      domains = 0;
      domains_str = tor_strndup(cfg+1, closebracket-cfg-1);
      domains_list = smartlist_create();
      smartlist_split_string(domains_list, domains_str, ",", SPLIT_SKIP_SPACE,
                             -1);
      tor_free(domains_str);
      SMARTLIST_FOREACH(domains_list, const char *, domain,
          {
            if (!strcmp(domain, "*")) {
              domains = ~0u;
            } else {
              int d;
              int negate=0;
              if (*domain == '~') {
                negate = 1;
                ++domain;
              }
              d = parse_log_domain(domain);
              if (!d) {
                log_warn(LD_CONFIG, "No such loggging domain as %s", domain);
                err = 1;
              } else {
                if (negate)
                  neg_domains |= d;
                else
                  domains |= d;
              }
            }
          });
      SMARTLIST_FOREACH(domains_list, char *, d, tor_free(d));
      smartlist_free(domains_list);
      if (err)
        return -1;
      domains &= ~neg_domains;
      cfg = eat_whitespace(closebracket+1);
    } else {
      ++got_an_unqualified_range;
    }
    if (!strcasecmpstart(cfg, "file") ||
        !strcasecmpstart(cfg, "stderr") ||
        !strcasecmpstart(cfg, "stdout") ||
        !strcasecmpstart(cfg, "syslog")) {
      goto done;
    }
    if (got_an_unqualified_range > 1)
      return -1;

    space = strchr(cfg, ' ');
    dash = strchr(cfg, '-');
    if (!space)
      space = strchr(cfg, '\0');
    if (dash && dash < space) {
      sev_lo = tor_strndup(cfg, dash-cfg);
      sev_hi = tor_strndup(dash+1, space-(dash+1));
    } else {
      sev_lo = tor_strndup(cfg, space-cfg);
      sev_hi = tor_strdup("ERR");
    }
    low = parse_log_level(sev_lo);
    high = parse_log_level(sev_hi);
    tor_free(sev_lo);
    tor_free(sev_hi);
    if (low == -1)
      return -1;
    if (high == -1)
      return -1;

    got_anything = 1;
    for (i=low; i >= high; --i)
      severity_out->masks[SEVERITY_MASK_IDX(i)] |= domains;

    cfg = eat_whitespace(space);
  }

 done:
  *cfg_ptr = cfg;
  return got_anything ? 0 : -1;
}

/** Return the least severe log level that any current log is interested in. */
int
get_min_log_level(void)
{
  logfile_t *lf;
  int i;
  int min = LOG_ERR;
  for (lf = logfiles; lf; lf = lf->next) {
    for (i = LOG_DEBUG; i > min; --i)
      if (lf->severities->masks[SEVERITY_MASK_IDX(i)])
        min = i;
  }
  return min;
}

/** Switch all logs to output at most verbose level. */
void
switch_logs_debug(void)
{
  logfile_t *lf;
  int i;
  LOCK_LOGS();
  for (lf = logfiles; lf; lf=lf->next) {
    for (i = LOG_DEBUG; i >= LOG_ERR; --i)
      lf->severities->masks[SEVERITY_MASK_IDX(i)] = ~0u;
  }
  UNLOCK_LOGS();
}

#ifdef HAVE_EVENT_SET_LOG_CALLBACK
/** A string which, if it appears in a libevent log, should be ignored. */
static const char *suppress_msg = NULL;
/** Callback function passed to event_set_log() so we can intercept
 * log messages from libevent. */
static void
libevent_logging_callback(int severity, const char *msg)
{
  char buf[1024];
  size_t n;
  if (suppress_msg && strstr(msg, suppress_msg))
    return;
  n = strlcpy(buf, msg, sizeof(buf));
  if (n && n < sizeof(buf) && buf[n-1] == '\n') {
    buf[n-1] = '\0';
  }
  switch (severity) {
    case _EVENT_LOG_DEBUG:
      log(LOG_DEBUG, LD_NET, "Message from libevent: %s", buf);
      break;
    case _EVENT_LOG_MSG:
      log(LOG_INFO, LD_NET, "Message from libevent: %s", buf);
      break;
    case _EVENT_LOG_WARN:
      log(LOG_WARN, LD_GENERAL, "Warning from libevent: %s", buf);
      break;
    case _EVENT_LOG_ERR:
      log(LOG_ERR, LD_GENERAL, "Error from libevent: %s", buf);
      break;
    default:
      log(LOG_WARN, LD_GENERAL, "Message [%d] from libevent: %s",
          severity, buf);
      break;
  }
}
/** Set hook to intercept log messages from libevent. */
void
configure_libevent_logging(void)
{
  event_set_log_callback(libevent_logging_callback);
}
/** Ignore any libevent log message that contains <b>msg</b>. */
void
suppress_libevent_log_msg(const char *msg)
{
  suppress_msg = msg;
}
#else
void
configure_libevent_logging(void)
{
}
void
suppress_libevent_log_msg(const char *msg)
{
  (void)msg;
}
#endif

#if 0
static void
dump_log_info(logfile_t *lf)
{
  const char *tp;

  if (lf->filename) {
    printf("=== log into \"%s\" (%s-%s) (%stemporary)\n", lf->filename,
           sev_to_string(lf->min_loglevel),
           sev_to_string(lf->max_loglevel),
           lf->is_temporary?"":"not ");
  } else if (lf->is_syslog) {
    printf("=== syslog (%s-%s) (%stemporary)\n",
           sev_to_string(lf->min_loglevel),
           sev_to_string(lf->max_loglevel),
           lf->is_temporary?"":"not ");
  } else {
    printf("=== log (%s-%s) (%stemporary)\n",
           sev_to_string(lf->min_loglevel),
           sev_to_string(lf->max_loglevel),
           lf->is_temporary?"":"not ");
  }
}

void
describe_logs(void)
{
  logfile_t *lf;
  printf("==== BEGIN LOGS ====\n");
  for (lf = logfiles; lf; lf = lf->next)
    dump_log_info(lf);
  printf("==== END LOGS ====\n");
}
#endif